Tool-holder assembly



Feb. 12, 1952 s. P. BRUCE 2,585,733

TOOLHOLDER ASSEMBLY Filed Oct. 26, 1948 2 SHEETS-SHEET l .ZEZVEHZUP Sczzgord F. 51 1109 Feb. 12, 1952 s, BRUCE 2,585,733

T OOLHOLDER ASSEMBLY Filed Oct. 26, 1948 2SHEETS-SHEET 2 lllll Patented Feb. 12, 1952 TOOL-HOLDER ASSEMBLY Stanford P. Bruce, Detroit, Mich., assignor to Wheel Trueing Tool Company, Detroit, Mich, a corporation of Michigan Application October 26, 1948, Serial No. 56,499

1 Claim. 1

The present invention relates to a new and. improved type of tool holder assembly.

More particularly, the invention relates to a tool holder adapted for use with diamond dressing tools in mechanisms for dressing or trueing the surface of an abrasive wheel.

It is common practice to dress the surface of an abrasive wheel periodically by use of a diamond tool which is caused to traverse the surface of the abrasive wheel as the wheel rotates about its axis to dress or true the surface. Continued use of the diamond dressing tool tends to wear the surface of the diamond point unevenly with the result that the edge of the diamond is dulled and does not present a good cutting surface to the abrasive wheel. To overcome this dif ficulty, it has been suggested that the diamond point be secured in a rotatable mounting so that the diamond point may be periodically rotated, thus presenting a new sharp edge to the work.

4 This innovation presents a problem in that the working clearances that are necessary in the design of a rotatable tool holder give rise to an objectionable vibration of the tool during its operation, commonly known as chattering. This chattering effect tends to make the operation of the tool unsteady with the result that the dressing is not as accurate as it should be.

An object of the present invention is to provide a tool holder particularly adapted for use in diamond dressing tools which is capable of intermittent rotation, but in which the effects of chattering are substantially or completely eliminated.

Other and further objects of the invention will be apparent from the description of the attached sheets of drawings.

On the drawings:

Figure 1 is a view of the grinding wheel dressing mechanism assembled and in position for the dressing of an abrasive grinding wheel.

Figure 2 is a front end view of the assembly as shown in Figure 1.

Figure 3 is across-sectional View taken along the line IIIIII of Figure 2.

Figure 4 is an end view of the assembly with the indexing collar of the assembly removed.

Figure 5 is a cross-sectional view taken along the line vV-V of Figure 4, with parts in elevation.

Figure 6 is an exploded view of the assembly showing its component parts.

As shown on the drawings:

In Figure 1, reference numeral I0 denotes in general a guard positioned concentrically with a rotary abrasive wheel II. A slide I2 is positioned 2 within the guard I0 and holds the dressing mechanism in such a position that a proper drag angle is presented between the axis of the diamond tool and a true radius of the abrasive wheel passing through the point of the tool.

The shank portion I3a of body member I3 of the assembly is held in bore I2a of the slide I2 and is provided with a longitudinally extending notch I3b. A locking screw I4 is threaded into the slide I2 and into the notch I3b to hold the body member I3 rigidly against rotation. A locking collar I5 abuts against the body member I 3 and serves to secure a tool adapter IT within the'assembly. A knurled indexing collar I6 is mounted against the locking collar I5 and is secured to the tool adapter I1 which carries a diamond tool I8 provided with a diamond point I9. The diamond tool holder I8 is secured within the tool adapter I I by means of locking screw 20.

The collar I6 is provided with inscribed numerals IBa to guide the operator in the proper indexing of the tool during rotation. The collar I6 is also provided with a recessed portion I6b terminating in a threaded portion I 60 adapted to receive a set screw M to rigidly hold the tool adapter I! such that the tool holder I I is rotated upon rotation of indexing collar I6.

As best shown in Figure 3, body member I3 is provided with a radially extending flange portion I311 formed into a shoulder portion I32 having an internally threaded boss I3j for receiving locking screws 22 for securing the restraining collar I5 against the shoulder I36 and the flange I3d. The body member I3 is also provided with an internal bore 539 which extends into the shank I3a of the body member I3. The bore I3g in the body member I3 is adapted to rotatably mount the pilot I'Ia of a tool adapter I1. A bearing surface I3h is formed in the body member I3 for seating a radially flanged portion ll?) of the tool adapter I'I. As shown in Figure 3, the diameter of the radially extending flange portion I'Ib is somewhat less than that of the bearing surface I3h. The flange portion I'lb' is provided with peripheral notches I I0 for receiving ball detent means ,as will be hereinafter described. Disposed between the flange portion I'Ib of the tool adapter I! and the surface of the restraining collar I5 are an oilite bearing 23 and a resilient spring washer 24. The resilient spring washer 24 is held under compression by the restraining collar I5 to effect a thrust-bearing relationship between the flange portion Nb and the bearing surface I3h. This arrangement acts provided with an internal bore I'Id for receiving a conventional diamond point holder I8, which is locked in the tool adapter H by means of a locking screw 20 being inserted through an aperture He in the tool adapter I'I.

As best shown in Figure 5, a ball detent means is provided in the assembly to control the rotation of the tool adapter so that a uniform indexing of the tool may be accomplished. The shoulder I3e of body member I3 is provided with a bore I31 extending therethrough for receiving a spring 25 and ball 26. The spring 25 is compressed by locking collar I and urges the ball 26 into an appropriate notch I'Ic of the flanged portion IIb.

In normal operation, the tool will be indexed after each complete cycle of dress, consisting of two passes across the grinding wheel face. At such time, the operator merely turns the knurled indexing collar I6 to the next appropriate number, causing the balls 26 to drop in the next series of notches lie, in which position a new dressing edge is presented by the diamond point to the abrasive wheel to be dressed and maintained until the next dressing cycle has been completed. As a result, after a series of such indexing operations, the diamond point assumes a generally pyramidical shape most suitable for dressing abrasive wheels, and may be used for an indefinite period of time. In assembling the tool holder assembly of the present invention, the tool adapter I! is inserted into the body member I3 by means of the pilot I'Ia being inserted into the bore I3g of the body member I3, causing the flange I'Ib to seat against the bearing surface I3h of the body member-I3. The oilite bearing 23 is then inserted over the shoulder ll of the tool adapter I! and against the opposite face of the flange portion I 1b. Next, resilient spring washer 24 is also inserted over shoulder I If. It is to be noted that the positions of the bearing 23 and the spring washer 24 may be reversed without impairing the operation of the device. Next, the restraining collar I5 is inserted over the shoulder Hi and against the shoulder I3e of the body member I3 and is secured to the body member I3 by means of the locking screws 22 passed through bores I5a in the restraining collar I5, and threaded into the boss portions I3f on the body member I3. Thus, the containing collar I5 causes the spring washer 2:3 to be compressed and to urge the flange Iic against the bearing surface I3h at all times. Finally, the knurled indexing collar I6 is slipped over the shoulder Ilg and rigidly secured thereto by the insertion of a lock screw 2I threaded 4 into internally threaded portion IBc in collar I6 and against collar I'Ig. A conventional diamond holder I8 with a diamond point I9 may be inserted into the tool adapter I1 and secured therein by means of a lock nut 20 inserted through an aperture IIe in the tool adapter I'I.

It will be seen from the above description that the present invention provides a tool holder especially adapted for use in connection with diamond dressing tools and provides for intermittent manual rotation of the diamond tool thus maintaining the diamond tool in a sharp condition at all times, while eliminating the undesirable chattering or vibration of the tool during the dressing operation.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claim.

I claim as my invention:

In a supporting assembly for a pointed tool for use in the dressing of rotary work such as grinding wheels and the like, a holder having an axial pilot bore, an adapter having at one end a pilot rotatably journaled in said bore and having at its other and free end means for receiving and lockingly holding a pointed tool' in substantially axial alignment with said bore, said adapter including a radially extending flange between its said end and at substantially right angles to said pilot, radially disposed peripheral notches on said flange, rotary index control mechanism between the periphery of said flange and said holder comprising a radially urged resilient element carried by said holder for cooperation with the radial notches of said flange, resilient thrust resisting means in cooperation with a radial face of said flange between said flange and said tool receiving end of the adapter, and clamping means disposed on the tool receiving end of said adapter holding said resilient thrust means in efiective cooperation with the radial flange on said adapter. V

STANFORD P. BRUCE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Borse Mar. 4, 

